Now a day’s accidents are
increasing at a large pace, and various technologies are being introduced to
reduce the accidents. In this project we provide means of accident prevention
using eye blink wherein the vehicle is stopped immediately and intimated
wherever needed.
In this project we have two
sections. One is transmitter section which is located in the vehicle and
another one is Receiver section located in remote place (Police station, near
ones, etc). In the transmitter section the eye blink sensor is placed near the
eye to sense the blink count and this information is transmitted in the form of
pulses and is given to the Microcontroller. The Microcontroller uses this
information to compare with the normal eye blink programmed in the chip and if
any abnormal situation arises the vehicle is stopped with an alarm indication,
this operation is enabled by means of the driver circuit connected to the
vehicle motor and the signal is transmitted via RF-transmitter at the frequency
of 433.92 MHz. In the Receiver side the transmitted signal is received and the
signal is decoded and given to the Microcontroller, which uses this information
for displaying the alert message in the LCD as programmed, simultaneously a
buzzer alert is given.
LIST OF HARDWARE MODULES:
1.Power Supply for 8051
Microcontroller
This section describes how to generate +5V DC power supply
The power supply section is the important one. It should
deliver constant output regulated power supply for successful working of the
project. A 0-12V/1 mA transformer is used for this purpose. The primary of this
transformer is connected in to main supply through on/off switch& fuse for
protecting from overload and short circuit protection. The secondary is
connected to the diodes to convert 12V AC to 12V DC voltage. And filtered by
the capacitors, which is further regulated to +5v, by using IC 7805
Microcontroller
A microcontroller
(also microcontroller unit, MCU or µC) is a small computer on a single integrated
circuit consisting of a relatively simple CPU combined with support functions
such as a crystal oscillator, timers and etc. Microcontrollers are used in
automatically controlled products and devices, such as automobile engine
control systems, remote controls, office machines, appliances, power tools, and
toys. The input and output device or connected to port pins of the controller.
Typical input and output devices include switches, relays, solenoids, LEDs,
small or custom LCD displays, radio frequency devices, and sensors for data
such as temperature, humidity, light level etc. The device, such as GSM, GPS
and RFID are interfaced to the controller via serial communication i.e. TX and
RX pins.
2. ENCODER
The HT-12E IC encode 12-bits of information and serially
transmits this data on receipt of a Transmit Enable and a LOW signal on pin-14
/TE. Pin-17 the D_OUT pin of the HT-12E serially transmits whatever data
is available on pins 10, 11, 12 and 13, or D0, D1, D2 and D3.
3. RF TRANSMITTER
The TWS-434 transmitter accepts both linear and digital
inputs can operate from 1.5 to 12 Volts-DC, and makes building a miniature
hand-held RF transmitter very easy. The P2_0, P2_1, P2_2 and P2_3 pin of
controller is assumed as data transmit pins. The DATA_OUT pin of encoder is
connected to the DATA_IN pin of RF Transmitter and then the RF Transmitter
transmits the data to the receiver.
4. DECODER
The 212 series of decoders are capable of decoding
information’s that consist of N bits of address and 12_N bits of data. Of this
series, the HT12D is arranged to provide 8 address bits and 4 data bits, and
HT12F is used to decode 12 bits of address information. The VT, or valid
transmission pin of the HT-12D could signal the microcontroller to grab the
4-bits of data from the data output pins.
5.RF RECEIVER
The receiver also operates at 433.92MHz, and has a sensitivity of
3uV. The TWS-434 receiver operates from 4.5 to 5.5 volts-DC, and has both
linear and digital outputs. The P2_0, P2_1, P2_2 and P2_3 pin of controller is
assumed as data transmit pins. The DATA_OUT pin of RF Transmitter is connected
to the DATA_IN pin of DECODER and then the data is processed by the decoder.
4. RELAY
A relay is
an electrically operated switch. Electric
current through the coil of the relay creates a magnetic field which
attracts a lever and changes the
switch contacts. The coil current can be
on or off so relays have two switch positions and they are double-throw
(changeover) switches. A simple electromagnetic relay, such as the one taken
from a car in the first picture, is an adaptation of an electromagnet.
It consists of a coil
of wire surrounding a soft iron core, an iron yoke, which provides a
low reluctance path for magnetic flux, a movable
iron armature, and a set, or
sets, of contacts. The armature is hinged to the yoke and mechanically linked
to a moving contact or contacts. It is held in place by a spring
so that when the relay is deenergized there is an air gap in the magnetic
circuit. In this condition, one of the two sets of contacts in the relay
pictured is closed, and the other set is open. The P0_0, P0_1, P0_2 and P0_3
pin of controller is assumed as data transmit pins to the relay through relay
driver ULN 2003. ULN 2003 is just like a current driver.
Block Diagram
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